drivers/input/evdev.c

   1 /*
   2  * Event char devices, giving access to raw input device events.
   3  *
   4  * Copyright (c) 1999-2002 Vojtech Pavlik
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published by
   8  * the Free Software Foundation.
   9  */
  10
  11 #define EVDEV_MINOR_BASE        64
  12 #define EVDEV_MINORS            32
  13 #define EVDEV_BUFFER_SIZE       64
  14
  15 #include <linux/poll.h>
  16 #include <linux/sched.h>
  17 #include <linux/slab.h>
  18 #include <linux/module.h>
  19 #include <linux/init.h>
  20 #include <linux/input.h>
  21 #include <linux/major.h>
  22 #include <linux/device.h>
  23 #include "input-compat.h"
  24
  25 struct evdev {
  26         int exist;
  27         int open;
  28         int minor;
  29         struct input_handle handle;
  30         wait_queue_head_t wait;
  31         struct evdev_client *grab;
  32         struct list_head client_list;
  33         spinlock_t client_lock; /* protects client_list */
  34         struct mutex mutex;
  35         struct device dev;
  36 };
  37
  38 struct evdev_client {
  39         struct input_event buffer[EVDEV_BUFFER_SIZE];
  40         int head;
  41         int tail;
  42         spinlock_t buffer_lock; /* protects access to buffer, head and tail */
  43         struct fasync_struct *fasync;
  44         struct evdev *evdev;
  45         struct list_head node;
  46 };
  47
  48 static struct evdev *evdev_table[EVDEV_MINORS];
  49 static DEFINE_MUTEX(evdev_table_mutex);
  50
  51 static void evdev_pass_event(struct evdev_client *client,
  52                              struct input_event *event)
  53 {
  54         /*
  55          * Interrupts are disabled, just acquire the lock
  56          */
  57         spin_lock(&client->buffer_lock);
  58         client->buffer[client->head++] = *event;
  59         client->head &= EVDEV_BUFFER_SIZE - 1;
  60         spin_unlock(&client->buffer_lock);
  61
  62         kill_fasync(&client->fasync, SIGIO, POLL_IN);
  63 }
  64
  65 /*
  66  * Pass incoming event to all connected clients.
  67  */
  68 static void evdev_event(struct input_handle *handle,
  69                         unsigned int type, unsigned int code, int value)
  70 {
  71         struct evdev *evdev = handle->private;
  72         struct evdev_client *client;
  73         struct input_event event;
  74
  75         do_gettimeofday(&event.time);
  76         event.type = type;
  77         event.code = code;
  78         event.value = value;
  79
  80         rcu_read_lock();
  81
  82         client = rcu_dereference(evdev->grab);
  83         if (client)
  84                 evdev_pass_event(client, &event);
  85         else
  86                 list_for_each_entry_rcu(client, &evdev->client_list, node)
  87                         evdev_pass_event(client, &event);
  88
  89         rcu_read_unlock();
  90
  91         wake_up_interruptible(&evdev->wait);
  92 }
  93
  94 static int evdev_fasync(int fd, struct file *file, int on)
  95 {
  96         struct evdev_client *client = file->private_data;
  97
  98         return fasync_helper(fd, file, on, &client->fasync);
  99 }
 100
 101 static int evdev_flush(struct file *file, fl_owner_t id)
 102 {
 103         struct evdev_client *client = file->private_data;
 104         struct evdev *evdev = client->evdev;
 105         int retval;
 106
 107         retval = mutex_lock_interruptible(&evdev->mutex);
 108         if (retval)
 109                 return retval;
 110
 111         if (!evdev->exist)
 112                 retval = -ENODEV;
 113         else
 114                 retval = input_flush_device(&evdev->handle, file);
 115
 116         mutex_unlock(&evdev->mutex);
 117         return retval;
 118 }
 119
 120 static void evdev_free(struct device *dev)
 121 {
 122         struct evdev *evdev = container_of(dev, struct evdev, dev);
 123
 124         input_put_device(evdev->handle.dev);
 125         kfree(evdev);
 126 }
 127
 128 /*
 129  * Grabs an event device (along with underlying input device).
 130  * This function is called with evdev->mutex taken.
 131  */
 132 static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
 133 {
 134         int error;
 135
 136         if (evdev->grab)
 137                 return -EBUSY;
 138
 139         error = input_grab_device(&evdev->handle);
 140         if (error)
 141                 return error;
 142
 143         rcu_assign_pointer(evdev->grab, client);
 144         synchronize_rcu();
 145
 146         return 0;
 147 }
 148
 149 static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
 150 {
 151         if (evdev->grab != client)
 152                 return  -EINVAL;
 153
 154         rcu_assign_pointer(evdev->grab, NULL);
 155         synchronize_rcu();
 156         input_release_device(&evdev->handle);
 157
 158         return 0;
 159 }
 160
 161 static void evdev_attach_client(struct evdev *evdev,
 162                                 struct evdev_client *client)
 163 {
 164         spin_lock(&evdev->client_lock);
 165         list_add_tail_rcu(&client->node, &evdev->client_list);
 166         spin_unlock(&evdev->client_lock);
 167         synchronize_rcu();
 168 }
 169
 170 static void evdev_detach_client(struct evdev *evdev,
 171                                 struct evdev_client *client)
 172 {
 173         spin_lock(&evdev->client_lock);
 174         list_del_rcu(&client->node);
 175         spin_unlock(&evdev->client_lock);
 176         synchronize_rcu();
 177 }
 178
 179 static int evdev_open_device(struct evdev *evdev)
 180 {
 181         int retval;
 182
 183         retval = mutex_lock_interruptible(&evdev->mutex);
 184         if (retval)
 185                 return retval;
 186
 187         if (!evdev->exist)
 188                 retval = -ENODEV;
 189         else if (!evdev->open++) {
 190                 retval = input_open_device(&evdev->handle);
 191                 if (retval)
 192                         evdev->open--;
 193         }
 194
 195         mutex_unlock(&evdev->mutex);
 196         return retval;
 197 }
 198
 199 static void evdev_close_device(struct evdev *evdev)
 200 {
 201         mutex_lock(&evdev->mutex);
 202
 203         if (evdev->exist && !--evdev->open)
 204                 input_close_device(&evdev->handle);
 205
 206         mutex_unlock(&evdev->mutex);
 207 }
 208
 209 /*
 210  * Wake up users waiting for IO so they can disconnect from
 211  * dead device.
 212  */
 213 static void evdev_hangup(struct evdev *evdev)
 214 {
 215         struct evdev_client *client;
 216
 217         spin_lock(&evdev->client_lock);
 218         list_for_each_entry(client, &evdev->client_list, node)
 219                 kill_fasync(&client->fasync, SIGIO, POLL_HUP);
 220         spin_unlock(&evdev->client_lock);
 221
 222         wake_up_interruptible(&evdev->wait);
 223 }
 224
 225 static int evdev_release(struct inode *inode, struct file *file)
 226 {
 227         struct evdev_client *client = file->private_data;
 228         struct evdev *evdev = client->evdev;
 229
 230         mutex_lock(&evdev->mutex);
 231         if (evdev->grab == client)
 232                 evdev_ungrab(evdev, client);
 233         mutex_unlock(&evdev->mutex);
 234
 235         evdev_detach_client(evdev, client);
 236         kfree(client);
 237
 238         evdev_close_device(evdev);
 239         put_device(&evdev->dev);
 240
 241         return 0;
 242 }
 243
 244 static int evdev_open(struct inode *inode, struct file *file)
 245 {
 246         struct evdev *evdev;
 247         struct evdev_client *client;
 248         int i = iminor(inode) - EVDEV_MINOR_BASE;
 249         int error;
 250
 251         if (i >= EVDEV_MINORS)
 252                 return -ENODEV;
 253
 254         error = mutex_lock_interruptible(&evdev_table_mutex);
 255         if (error)
 256                 return error;
 257         evdev = evdev_table[i];
 258         if (evdev)
 259                 get_device(&evdev->dev);
 260         mutex_unlock(&evdev_table_mutex);
 261
 262         if (!evdev)
 263                 return -ENODEV;
 264
 265         client = kzalloc(sizeof(struct evdev_client), GFP_KERNEL);
 266         if (!client) {
 267                 error = -ENOMEM;
 268                 goto err_put_evdev;
 269         }
 270
 271         spin_lock_init(&client->buffer_lock);
 272         client->evdev = evdev;
 273         evdev_attach_client(evdev, client);
 274
 275         error = evdev_open_device(evdev);
 276         if (error)
 277                 goto err_free_client;
 278
 279         file->private_data = client;
 280         return 0;
 281
 282  err_free_client:
 283         evdev_detach_client(evdev, client);
 284         kfree(client);
 285  err_put_evdev:
 286         put_device(&evdev->dev);
 287         return error;
 288 }
 289
 290 static ssize_t evdev_write(struct file *file, const char __user *buffer,
 291                            size_t count, loff_t *ppos)
 292 {
 293         struct evdev_client *client = file->private_data;
 294         struct evdev *evdev = client->evdev;
 295         struct input_event event;
 296         int retval;
 297
 298         retval = mutex_lock_interruptible(&evdev->mutex);
 299         if (retval)
 300                 return retval;
 301
 302         if (!evdev->exist) {
 303                 retval = -ENODEV;
 304                 goto out;
 305         }
 306
 307         while (retval < count) {
 308
 309                 if (input_event_from_user(buffer + retval, &event)) {
 310                         retval = -EFAULT;
 311                         goto out;
 312                 }
 313
 314                 input_inject_event(&evdev->handle,
 315                                    event.type, event.code, event.value);
 316                 retval += input_event_size();
 317         }
 318
 319  out:
 320         mutex_unlock(&evdev->mutex);
 321         return retval;
 322 }
 323
 324 static int evdev_fetch_next_event(struct evdev_client *client,
 325                                   struct input_event *event)
 326 {
 327         int have_event;
 328
 329         spin_lock_irq(&client->buffer_lock);
 330
 331         have_event = client->head != client->tail;
 332         if (have_event) {
 333                 *event = client->buffer[client->tail++];
 334                 client->tail &= EVDEV_BUFFER_SIZE - 1;
 335         }
 336
 337         spin_unlock_irq(&client->buffer_lock);
 338
 339         return have_event;
 340 }
 341
 342 static ssize_t evdev_read(struct file *file, char __user *buffer,
 343                           size_t count, loff_t *ppos)
 344 {
 345         struct evdev_client *client = file->private_data;
 346         struct evdev *evdev = client->evdev;
 347         struct input_event event;
 348         int retval;
 349
 350         if (count < input_event_size())
 351                 return -EINVAL;
 352
 353         if (client->head == client->tail && evdev->exist &&
 354             (file->f_flags & O_NONBLOCK))
 355                 return -EAGAIN;
 356
 357         retval = wait_event_interruptible(evdev->wait,
 358                 client->head != client->tail || !evdev->exist);
 359         if (retval)
 360                 return retval;
 361
 362         if (!evdev->exist)
 363                 return -ENODEV;
 364
 365         while (retval + input_event_size() <= count &&
 366                evdev_fetch_next_event(client, &event)) {
 367
 368                 if (input_event_to_user(buffer + retval, &event))
 369                         return -EFAULT;
 370
 371                 retval += input_event_size();
 372         }
 373
 374         return retval;
 375 }
 376
 377 /* No kernel lock - fine */
 378 static unsigned int evdev_poll(struct file *file, poll_table *wait)
 379 {
 380         struct evdev_client *client = file->private_data;
 381         struct evdev *evdev = client->evdev;
 382
 383         poll_wait(file, &evdev->wait, wait);
 384         return ((client->head == client->tail) ? 0 : (POLLIN | POLLRDNORM)) |
 385                 (evdev->exist ? 0 : (POLLHUP | POLLERR));
 386 }
 387
 388 #ifdef CONFIG_COMPAT
 389
 390 #define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
 391 #define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
 392
 393 #ifdef __BIG_ENDIAN
 394 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 395                         unsigned int maxlen, void __user *p, int compat)
 396 {
 397         int len, i;
 398
 399         if (compat) {
 400                 len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
 401                 if (len > maxlen)
 402                         len = maxlen;
 403
 404                 for (i = 0; i < len / sizeof(compat_long_t); i++)
 405                         if (copy_to_user((compat_long_t __user *) p + i,
 406                                          (compat_long_t *) bits +
 407                                                 i + 1 - ((i % 2) << 1),
 408                                          sizeof(compat_long_t)))
 409                                 return -EFAULT;
 410         } else {
 411                 len = BITS_TO_LONGS(maxbit) * sizeof(long);
 412                 if (len > maxlen)
 413                         len = maxlen;
 414
 415                 if (copy_to_user(p, bits, len))
 416                         return -EFAULT;
 417         }
 418
 419         return len;
 420 }
 421 #else
 422 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 423                         unsigned int maxlen, void __user *p, int compat)
 424 {
 425         int len = compat ?
 426                         BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
 427                         BITS_TO_LONGS(maxbit) * sizeof(long);
 428
 429         if (len > maxlen)
 430                 len = maxlen;
 431
 432         return copy_to_user(p, bits, len) ? -EFAULT : len;
 433 }
 434 #endif /* __BIG_ENDIAN */
 435
 436 #else
 437
 438 static int bits_to_user(unsigned long *bits, unsigned int maxbit,
 439                         unsigned int maxlen, void __user *p, int compat)
 440 {
 441         int len = BITS_TO_LONGS(maxbit) * sizeof(long);
 442
 443         if (len > maxlen)
 444                 len = maxlen;
 445
 446         return copy_to_user(p, bits, len) ? -EFAULT : len;
 447 }
 448
 449 #endif /* CONFIG_COMPAT */
 450
 451 static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
 452 {
 453         int len;
 454
 455         if (!str)
 456                 return -ENOENT;
 457
 458         len = strlen(str) + 1;
 459         if (len > maxlen)
 460                 len = maxlen;
 461
 462         return copy_to_user(p, str, len) ? -EFAULT : len;
 463 }
 464
 465 #define OLD_KEY_MAX     0x1ff
 466 static int handle_eviocgbit(struct input_dev *dev, unsigned int cmd, void __user *p, int compat_mode)
 467 {
 468         static unsigned long keymax_warn_time;
 469         unsigned long *bits;
 470         int len;
 471
 472         switch (_IOC_NR(cmd) & EV_MAX) {
 473
 474         case      0: bits = dev->evbit;  len = EV_MAX;  break;
 475         case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
 476         case EV_REL: bits = dev->relbit; len = REL_MAX; break;
 477         case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
 478         case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
 479         case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
 480         case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
 481         case EV_FF:  bits = dev->ffbit;  len = FF_MAX;  break;
 482         case EV_SW:  bits = dev->swbit;  len = SW_MAX;  break;
 483         default: return -EINVAL;
 484         }
 485
 486         /*
 487          * Work around bugs in userspace programs that like to do
 488          * EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
 489          * should be in bytes, not in bits.
 490          */
 491         if ((_IOC_NR(cmd) & EV_MAX) == EV_KEY && _IOC_SIZE(cmd) == OLD_KEY_MAX) {
 492                 len = OLD_KEY_MAX;
 493                 if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
 494                         printk(KERN_WARNING
 495                                 "evdev.c(EVIOCGBIT): Suspicious buffer size %u, "
 496                                 "limiting output to %zu bytes. See "
 497                                 "http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
 498                                 OLD_KEY_MAX,
 499                                 BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
 500         }
 501
 502         return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
 503 }
 504 #undef OLD_KEY_MAX
 505
 506 static long evdev_do_ioctl(struct file *file, unsigned int cmd,
 507                            void __user *p, int compat_mode)
 508 {
 509         struct evdev_client *client = file->private_data;
 510         struct evdev *evdev = client->evdev;
 511         struct input_dev *dev = evdev->handle.dev;
 512         struct input_absinfo abs;
 513         struct ff_effect effect;
 514         int __user *ip = (int __user *)p;
 515         int i, t, u, v;
 516         int error;
 517
 518         switch (cmd) {
 519
 520         case EVIOCGVERSION:
 521                 return put_user(EV_VERSION, ip);
 522
 523         case EVIOCGID:
 524                 if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
 525                         return -EFAULT;
 526                 return 0;
 527
 528         case EVIOCGREP:
 529                 if (!test_bit(EV_REP, dev->evbit))
 530                         return -ENOSYS;
 531                 if (put_user(dev->rep[REP_DELAY], ip))
 532                         return -EFAULT;
 533                 if (put_user(dev->rep[REP_PERIOD], ip + 1))
 534                         return -EFAULT;
 535                 return 0;
 536
 537         case EVIOCSREP:
 538                 if (!test_bit(EV_REP, dev->evbit))
 539                         return -ENOSYS;
 540                 if (get_user(u, ip))
 541                         return -EFAULT;
 542                 if (get_user(v, ip + 1))
 543                         return -EFAULT;
 544
 545                 input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
 546                 input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
 547
 548                 return 0;
 549
 550         case EVIOCGKEYCODE:
 551                 if (get_user(t, ip))
 552                         return -EFAULT;
 553
 554                 error = input_get_keycode(dev, t, &v);
 555                 if (error)
 556                         return error;
 557
 558                 if (put_user(v, ip + 1))
 559                         return -EFAULT;
 560
 561                 return 0;
 562
 563         case EVIOCSKEYCODE:
 564                 if (get_user(t, ip) || get_user(v, ip + 1))
 565                         return -EFAULT;
 566
 567                 return input_set_keycode(dev, t, v);
 568
 569         case EVIOCRMFF:
 570                 return input_ff_erase(dev, (int)(unsigned long) p, file);
 571
 572         case EVIOCGEFFECTS:
 573                 i = test_bit(EV_FF, dev->evbit) ?
 574                                 dev->ff->max_effects : 0;
 575                 if (put_user(i, ip))
 576                         return -EFAULT;
 577                 return 0;
 578
 579         case EVIOCGRAB:
 580                 if (p)
 581                         return evdev_grab(evdev, client);
 582                 else
 583                         return evdev_ungrab(evdev, client);
 584
 585         default:
 586
 587                 if (_IOC_TYPE(cmd) != 'E')
 588                         return -EINVAL;
 589
 590                 if (_IOC_DIR(cmd) == _IOC_READ) {
 591
 592                         if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
 593                                 return handle_eviocgbit(dev, cmd, p, compat_mode);
 594
 595                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGKEY(0)))
 596                                 return bits_to_user(dev->key, KEY_MAX, _IOC_SIZE(cmd),
 597                                                     p, compat_mode);
 598
 599                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGLED(0)))
 600                                 return bits_to_user(dev->led, LED_MAX, _IOC_SIZE(cmd),
 601                                                     p, compat_mode);
 602
 603                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSND(0)))
 604                                 return bits_to_user(dev->snd, SND_MAX, _IOC_SIZE(cmd),
 605                                                     p, compat_mode);
 606
 607                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGSW(0)))
 608                                 return bits_to_user(dev->sw, SW_MAX, _IOC_SIZE(cmd),
 609                                                     p, compat_mode);
 610
 611                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGNAME(0)))
 612                                 return str_to_user(dev->name, _IOC_SIZE(cmd), p);
 613
 614                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGPHYS(0)))
 615                                 return str_to_user(dev->phys, _IOC_SIZE(cmd), p);
 616
 617                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCGUNIQ(0)))
 618                                 return str_to_user(dev->uniq, _IOC_SIZE(cmd), p);
 619
 620                         if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
 621
 622                                 t = _IOC_NR(cmd) & ABS_MAX;
 623
 624                                 abs.value = dev->abs[t];
 625                                 abs.minimum = dev->absmin[t];
 626                                 abs.maximum = dev->absmax[t];
 627                                 abs.fuzz = dev->absfuzz[t];
 628                                 abs.flat = dev->absflat[t];
 629                                 abs.resolution = dev->absres[t];
 630
 631                                 if (copy_to_user(p, &abs, min_t(size_t,
 632                                                                 _IOC_SIZE(cmd),
 633                                                                 sizeof(struct input_absinfo))))
 634                                         return -EFAULT;
 635
 636                                 return 0;
 637                         }
 638
 639                 }
 640
 641                 if (_IOC_DIR(cmd) == _IOC_WRITE) {
 642
 643                         if (_IOC_NR(cmd) == _IOC_NR(EVIOCSFF)) {
 644
 645                                 if (input_ff_effect_from_user(p, _IOC_SIZE(cmd), &effect))
 646                                         return -EFAULT;
 647
 648                                 error = input_ff_upload(dev, &effect, file);
 649
 650                                 if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
 651                                         return -EFAULT;
 652
 653                                 return error;
 654                         }
 655
 656                         if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
 657
 658                                 t = _IOC_NR(cmd) & ABS_MAX;
 659
 660                                 if (copy_from_user(&abs, p, min_t(size_t,
 661                                                                   _IOC_SIZE(cmd),
 662                                                                   sizeof(struct input_absinfo))))
 663                                         return -EFAULT;
 664
 665                                 /*
 666                                  * Take event lock to ensure that we are not
 667                                  * changing device parameters in the middle
 668                                  * of event.
 669                                  */
 670                                 spin_lock_irq(&dev->event_lock);
 671
 672                                 dev->abs[t] = abs.value;
 673                                 dev->absmin[t] = abs.minimum;
 674                                 dev->absmax[t] = abs.maximum;
 675                                 dev->absfuzz[t] = abs.fuzz;
 676                                 dev->absflat[t] = abs.flat;
 677                                 dev->absres[t] = _IOC_SIZE(cmd) < sizeof(struct input_absinfo) ?
 678                                                         0 : abs.resolution;
 679
 680                                 spin_unlock_irq(&dev->event_lock);
 681
 682                                 return 0;
 683                         }
 684                 }
 685         }
 686         return -EINVAL;
 687 }
 688
 689 static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
 690                                 void __user *p, int compat_mode)
 691 {
 692         struct evdev_client *client = file->private_data;
 693         struct evdev *evdev = client->evdev;
 694         int retval;
 695
 696         retval = mutex_lock_interruptible(&evdev->mutex);
 697         if (retval)
 698                 return retval;
 699
 700         if (!evdev->exist) {
 701                 retval = -ENODEV;
 702                 goto out;
 703         }
 704
 705         retval = evdev_do_ioctl(file, cmd, p, compat_mode);
 706
 707  out:
 708         mutex_unlock(&evdev->mutex);
 709         return retval;
 710 }
 711
 712 static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 713 {
 714         return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
 715 }
 716
 717 #ifdef CONFIG_COMPAT
 718 static long evdev_ioctl_compat(struct file *file,
 719                                 unsigned int cmd, unsigned long arg)
 720 {
 721         return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
 722 }
 723 #endif
 724
 725 static const struct file_operations evdev_fops = {
 726         .owner          = THIS_MODULE,
 727         .read           = evdev_read,
 728         .write          = evdev_write,
 729         .poll           = evdev_poll,
 730         .open           = evdev_open,
 731         .release        = evdev_release,
 732         .unlocked_ioctl = evdev_ioctl,
 733 #ifdef CONFIG_COMPAT
 734         .compat_ioctl   = evdev_ioctl_compat,
 735 #endif
 736         .fasync         = evdev_fasync,
 737         .flush          = evdev_flush
 738 };
 739
 740 static int evdev_install_chrdev(struct evdev *evdev)
 741 {
 742         /*
 743          * No need to do any locking here as calls to connect and
 744          * disconnect are serialized by the input core
 745          */
 746         evdev_table[evdev->minor] = evdev;
 747         return 0;
 748 }
 749
 750 static void evdev_remove_chrdev(struct evdev *evdev)
 751 {
 752         /*
 753          * Lock evdev table to prevent race with evdev_open()
 754          */
 755         mutex_lock(&evdev_table_mutex);
 756         evdev_table[evdev->minor] = NULL;
 757         mutex_unlock(&evdev_table_mutex);
 758 }
 759
 760 /*
 761  * Mark device non-existent. This disables writes, ioctls and
 762  * prevents new users from opening the device. Already posted
 763  * blocking reads will stay, however new ones will fail.
 764  */
 765 static void evdev_mark_dead(struct evdev *evdev)
 766 {
 767         mutex_lock(&evdev->mutex);
 768         evdev->exist = 0;
 769         mutex_unlock(&evdev->mutex);
 770 }
 771
 772 static void evdev_cleanup(struct evdev *evdev)
 773 {
 774         struct input_handle *handle = &evdev->handle;
 775
 776         evdev_mark_dead(evdev);
 777         evdev_hangup(evdev);
 778         evdev_remove_chrdev(evdev);
 779
 780         /* evdev is marked dead so no one else accesses evdev->open */
 781         if (evdev->open) {
 782                 input_flush_device(handle, NULL);
 783                 input_close_device(handle);
 784         }
 785 }
 786
 787 /*
 788  * Create new evdev device. Note that input core serializes calls
 789  * to connect and disconnect so we don't need to lock evdev_table here.
 790  */
 791 static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
 792                          const struct input_device_id *id)
 793 {
 794         struct evdev *evdev;
 795         int minor;
 796         int error;
 797
 798         for (minor = 0; minor < EVDEV_MINORS; minor++)
 799                 if (!evdev_table[minor])
 800                         break;
 801
 802         if (minor == EVDEV_MINORS) {
 803                 printk(KERN_ERR "evdev: no more free evdev devices\n");
 804                 return -ENFILE;
 805         }
 806
 807         evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
 808         if (!evdev)
 809                 return -ENOMEM;
 810
 811         INIT_LIST_HEAD(&evdev->client_list);
 812         spin_lock_init(&evdev->client_lock);
 813         mutex_init(&evdev->mutex);
 814         init_waitqueue_head(&evdev->wait);
 815
 816         dev_set_name(&evdev->dev, "event%d", minor);
 817         evdev->exist = 1;
 818         evdev->minor = minor;
 819
 820         evdev->handle.dev = input_get_device(dev);
 821         evdev->handle.name = dev_name(&evdev->dev);
 822         evdev->handle.handler = handler;
 823         evdev->handle.private = evdev;
 824
 825         evdev->dev.devt = MKDEV(INPUT_MAJOR, EVDEV_MINOR_BASE + minor);
 826         evdev->dev.class = &input_class;
 827         evdev->dev.parent = &dev->dev;
 828         evdev->dev.release = evdev_free;
 829         device_initialize(&evdev->dev);
 830
 831         error = input_register_handle(&evdev->handle);
 832         if (error)
 833                 goto err_free_evdev;
 834
 835         error = evdev_install_chrdev(evdev);
 836         if (error)
 837                 goto err_unregister_handle;
 838
 839         error = device_add(&evdev->dev);
 840         if (error)
 841                 goto err_cleanup_evdev;
 842
 843         return 0;
 844
 845  err_cleanup_evdev:
 846         evdev_cleanup(evdev);
 847  err_unregister_handle:
 848         input_unregister_handle(&evdev->handle);
 849  err_free_evdev:
 850         put_device(&evdev->dev);
 851         return error;
 852 }
 853
 854 static void evdev_disconnect(struct input_handle *handle)
 855 {
 856         struct evdev *evdev = handle->private;
 857
 858         device_del(&evdev->dev);
 859         evdev_cleanup(evdev);
 860         input_unregister_handle(handle);
 861         put_device(&evdev->dev);
 862 }
 863
 864 static const struct input_device_id evdev_ids[] = {
 865         { .driver_info = 1 },   /* Matches all devices */
 866         { },                    /* Terminating zero entry */
 867 };
 868
 869 MODULE_DEVICE_TABLE(input, evdev_ids);
 870
 871 static struct input_handler evdev_handler = {
 872         .event          = evdev_event,
 873         .connect        = evdev_connect,
 874         .disconnect     = evdev_disconnect,
 875         .fops           = &evdev_fops,
 876         .minor          = EVDEV_MINOR_BASE,
 877         .name           = "evdev",
 878         .id_table       = evdev_ids,
 879 };
 880
 881 static int __init evdev_init(void)
 882 {
 883         return input_register_handler(&evdev_handler);
 884 }
 885
 886 static void __exit evdev_exit(void)
 887 {
 888         input_unregister_handler(&evdev_handler);
 889 }
 890
 891 module_init(evdev_init);
 892 module_exit(evdev_exit);
 893
 894 MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
 895 MODULE_DESCRIPTION("Input driver event char devices");
 896 MODULE_LICENSE("GPL");